I think copyright is a capillary point. Not all the people knows the copyright of US as well as related citizens. It needs hundred years of time reading this law to understand bunch of legal statements.
In my country when someone publish a picture it means other people are allowed to redistribute it. So he may not publish his picture in such a high resolution to worth for commercial purposes.
It may be similar or such in other countries. It doesn't mean they have preconceived opinion. I personally don't think that other people who mentioned to redistribute some documents from here are evil thieves.
To tell you the the truth I was wondered when saw anger to a guy who redistribute a picture from Himalaya with credits to SP. Till now I thought I was not a bad job. It's very common in many countries.
In my opinion forcing someone to ask for a special permission to redistribute a picture he previously published in a public area is a kind of restricting information flow. I just imagine a condition that I may saw a picture and want to redistribute it or translate a document in to another language. As I found from this topic I must find the guy who send it here and ask for permission.
Now what if the guy has left here and I couldn't find him?
and what if he says this is not his own and point me to another guy?
and there are many such questions in practice.

So I propose to focus just on commercial purposes and the guys who earned money from the documents published here and let amateurs and non-commercials to redistribute the documents (with credits to SP) in order to globalization of modern scientific mountaineering in allover the world. It's just an idea.

You can block the "copy image" feature in most browsers, but that doesn't stop people from doing a screen capture and cropping the margins of the captured image. You can also block the linking of content.

It's pretty much impossible to keep people from copying images. You can make it slightly more difficult, but that's about it, and even that is usually quite some work. Best to make your peace with the basic fact that you can't do much about it, except complain once the deed has been perpetrated.

When visiting a web site, it is so easy to click and save with a mouse button when one sees a graphic image or photo that one likes, or to view the source code and copy part of or all of the HTML coding because one "likes the way this or that was done" or one "wants a similar layout", or to copy original writings because "that person expresses this or that so well". The general (and incorrect) notion is that anything that is on the internet is public domain and may be taken without permission from the creator/owner. Some people actually think (incorrectly) that just because bits of web pages may be stored in one's cache, or because certain browsers allow one to do "file save as" moves or anything similar one may use such material as one wishes. This is false.